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G. P. CUMMINGS. MACHINE FOR DRESSING THE OOMMUTATORS IN DYNAMO MACHINES.

No. 443,270. Patented Dec. 23, 1890.

I UNITED STATES- PATENT OFFICE.

GEORGE P. CUMMINGS, OF NEIV YORK, N. Y.

MACHINE FOR DRESSING THE-COMMUTATORS IN DYNAMO-MACHINES.

SPECIFICATION forming part of Letters Patent No. 443,270, dated December 23, 1890.

Application filed April 18, 1890. I Serial No.348,518. (Nomotleh) To all whom it may concern:

Be it known that I, GEORGE P. CUMMINGS, of the city,county, and State of New York, have invented anew and useful Machine for Dressing the Oommutators in Dynamo-Machines; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, making apart of this specification;

The object ofmy invention is to provide a simple effective attachment for a dynamomachine, by means whereof the commutators when so worn, roughened, or scratched by the action of the brushes thereon as to 0perate inefficiently may be quickly and accurately dressed and trued up in exact form, even by an unskilled workman, thereby remedying the loss of time and the necessity of a trained mechanic for the purpose required in the truing up of a commutator by hand, as now commonly practiced.

My invention consists in the combination, substantially as hereinafter described and claimed, with a spindle adapted to be substituted in place of the device which carries the brushes in a dynamo and to be secured by the same means and occupy substantially the same relative position in the machine as the brush-bar for the commutator-brushes, of a grinding or abrading and polishing wheel mounted to move longitudinally upon a sleeve revolving freely upon said spindle, and de-' vices for gearing the sleeve directly with the commutator.

In the accompanying drawings, Figure 1 is an elevation of one end of the commutator in a dynamo, showing the application of my dressing-machine thereto; Fig. 2, an irregular longitudinal section, on an enlarged scale, in line w w of Figs. 1 and 3; Fig. 3, a transverse section in line a: 90 of Fig. 2; Fig. 4:, a similar section in line y y of Fig. 2, and Fig. 5 a transverse section in line z z of Fig.

Similar letters indicate like parts in all the figures.

A, Figsl and 3, represents the commutator in a dynamo-machine, of any of the well known forms of construction, and B the arm to which the device carrying the commutatorbrushes is attached in the customary manner, viz., by passing a lug projecting from the plate to which the brush rod or bar is usually secured through an aperture in the end of the arm 13, so as to bring the outer face of said plate to a bearing against the inner face of the arm, and then making it fast by a nut screwing upon the outer end of the lug against the outer face of the bar.

0 represents a plate adapted to be substituted for the brush-plate, and which is provided with a lug D, formed thereon to pass through the aperture formed in the end of the arm B for the attachment of the brush-plate.

A nut D ,screwing upon the outer end of the,

lug, serves to make the plate fast to the arm, as illustrated in Fig. 2. The plate Ois thus made to project above the arm parallel therewith, and a transverse 'slot Etherein (see Fig. 3) is brought thereby in line horizontally with the axis of the commutator.

F is the spindle for the support of the abrading-wheel. The inner end of this spindle is reduced in diameter and is flattened to pass through the slot E and form a shoulder a,

which,with an encircling collar G, formed upon the spindle, is brought to abearing against the inner face of the plate 0. The spindle is made fast by means of a nut F, fitted to screw upon its projecting end against the opposite face of the plate 0, as shown in Fig. 2. The spindle F is thus supported to extend at a right angle from the plate 0 in front of the commutator and in exact parallelism with its axis, and the slot E permits of an adjustment thereof to and from the commutator without disturbing its alignment therewith. This adj ustment is effected by means of an adjustingscrew I (see Fig. working through one end of the plate O to enter the proximate end of the slot E, as shown in Fig. 3, and bear laterally against the end of the spindle. Along sleeve H, terminating at its inner end in a pulley H and provided with a longitudinal groove 6, extending from end to end thereof, is fitted to revolve freely upon the spindle F, and is confined thereon by means of a nut F screwing upon its outer end. A second sleeve J is fitted upon the revolving sleeve H to move freely longitudinally thereon, but is prevented from revolving independently thereof by means of a spline f entering the 1on gitudinal groove 6. One end of the sliding sleeve J terminates in an annular flange K,

and the opposite end is threadedto receive a nut L screwing thereon.

A grinding or polishing wheel M, of emery or other suitable grinding or abrading material, is fitted upon the sliding sleeve J against its flange K,and is secured by means of the nut L, a washer Nbeing interposed between them. 3y this means a rotary motion is imparted to the wheel from the sleeve II, while it maybe moved longitudinally thereon from one end of the commutator to the other in accurate parallelism with its axis. To facilitate this lateral movement of the wheel the nut L is extended, and a loose collar W is fitted to turn freely upon the body thereof, as shown in Figs. 1 and 2, this collar being of such width as to permit it to be readily seized with the thumb and first finger and serve as a handle by which to move the wheel. The rotation of the sleeve II is produced in unison with that of the commutator A by means of a friction gear wheel O, interposed between the periphery of the head or encircling flange A at the outer end of the commutator, and the 'periphery of the corresponding pulley II on the end of the sleeve to bear against each. This friction gear-wheel 0 remains in constant engagement with the pulley II, being pivoted upon a stud 1, which is secured, as shown in Fig. 5, by means of a screw P, eccentric to its axis to the side of an arm S, projecting from a plate S, which is fitted to swing upon the spindle l alongside the plate 0, to which the spindle is secured. This plate S is formed with a slot T therein, curved upon an are having the axis of the spindle as its center, and is made fast by means of a thumb-nut working upon a screw R, projecting through said slot from an extension 0 of the plate 0. By loosening this thumb-nut R the arm S may be swung upon the spindle F as a center, so as to adjust the bearing of the gear-wheel 0 against the commutator A, while an adjustment of said gearwheel to adapt it to variations in the size of the flange A on the commutator may be effected by turning the stud I upon its cccentric pivotal screw P.

In the use of my invention the brush'bar in the dynamo is removed from the support ing-arm l5, and in place thereof the plate G, carrying the spindle F for the drcssing-wheel H, is attached to said arm by means of the stud or offset D and nut D, whereby the spindle F is brought into exact parallelism with the axis of the commutator, and in such proximity thereto as to allow the friction gean wheel 0, which engages the collar II on the rotating sleeve II, to contact with the head or annular flange A upon the outer end of the commutator, and at the same time bring the periphery of the grindingwhcel M into contact with the face of the commutator. The

grinding-wheel, being thus made to revolve in unison with the commutator by means of the gear-wheel O, is then moved by hand back and forth upon the sleeve II, over the face of the commutator, to polish it off and true it up, its pressure against the same being adjusted as required by means of the set screw I.

It is evident that by this simple appliance the face of the commutator may be dressed with the utmost exactitude and nicely without danger of injury thereto and without the need of special skill on the part of the operator.

I claim as my invention- 1. The combination, in a machine for dressing the face of dynamo-commutators, of a spindle, an encircling sleeve rotating thereon, a second sleeve sliding longitudinally upon the first and having a spline'and-groove connection therewith, a grinding or abrading wheel fitted upon said sliding sleeve, means, substantially as described, for attaching the spindle to the dynamo in parallelism with the commutator, and an adj ustable gear for connecting the rotating spindle with the dynamo, whereby the two are made to revolve in unison, substantially in the manner and for the purpose herein set forth.

2. In a machine for dressing dynamo-commutators, the combination, with a detachable plate adapted to be made fast to the arm of the dynamo at a right angle with the axis of its commutator, of a spindle secured to said plate at a right angle therewith, an extended sleeve rotating upon said spindle and carrying a pulley at its inner end, a grindingwheel fitted upon said sleeve to partake of its rotary movement, but left free to he moved longitudinally thereon, an arm swinging upon the inner end of the spindle, a friction gearwheel pivoted upon said arm in contact with the pulley on the sleeve, and a device, substantially as described, for making fast the arm when adjusted, whereby the grindingwheel may be geared to the commutator, substantially in the manner and for the purpose herein set forth.

3. In a machine for dressing dynamo-commutators, the combination, with the spindle, the sleeve rotating upon the spindle, and the grinding-wheel mounted on the sleeve, of the adjustable friction gear-wheel by which said sleeve is driven, the adjustable stud upon which said gear-wheel is pivoted, and the cocentricpin upon which said stud is supported, substantially in the manner and for the purpose herein set forth.

a. The combination, in a machine for dressing dynamo'commutators, with the spindle, its supporting-plate, the sleeve rotating upon the spindle, and the grinding-wheel mounted upon the sleeve, of a plate swinging upon the spindle as its axis and slotted upon an are having said axis as its center, a screw projecting through said slot into the supportingplate and fitted with a thumb-n ut, and a friction gear-wheel pivoted upon the swinging plate to engage the rotating sleeve, substantially in the manner and for the purpose herein set forth.

5. Ihe combination, in a machine for dressing dynamo-commutators with the spindle, the grinding-wheel mounted thereon, the plate to which the spindle is secured, and means for attaching the plate to the dynamo and supporting the spindle in parallelism with its commutator, of a longitudinal slot formed in said plate at a right angle to the axis of the commutator to receive the end of the spindle, means for securing the end of the spindle in said slot, and a set-screw extending parallel with the length of the slot 

